This invention generally relates to angioplasty procedures such as percutaneous transluminal coronary angioplasty (PTCA) and particularly to inflation/deflation devices for use in such procedures.
In PTCA procedures, a dilatation catheter having an inflatable, relatively inelastic balloon on the distal end thereof is advanced through a patient's arterial system until the balloon crosses the atherosclerotic lesion to be dilated. The balloon is inflated to a predetermined size with radiopaque liquid by syringe-like inflation device mounted on the proximal end of the dilatation catheter to dilate the lesion and then deflated so that the catheter can be removed from the stenotic region and blood flow resumed.
The first step of the procedure is to percutaneously introduce a guiding catheter having a preformed distal tip into the patient's arterial system (e.g. the femoral artery) and advance the catheter therein until preformed distal tip thereof is seated within the ostium of the appropriate coronary artery. A guidewire is preloaded within an inner lumen of the dilatation catheter and both are then advanced through the previously positioned guiding catheter to the distal end thereof. The guidewire is first advanced out of the distal tip of the guiding catheter into the patient's coronary artery until the distal end of the guidewire crosses the stenotic arterial region to be dilated. The dilatation catheter is then advanced out of the guiding catheter over the guidewire until the inflatable balloon on the distal end thereof is positioned across the stenosis. The balloon is inflated with radiopaque liquid to a relatively high pressure (e.g. up to 8 atmospheres or more) by the inflation device to dilate the stenosis. After the dilatation, the balloon is deflated and the catheter removed.
For a more detailed description of the procedures and the devices used in such procedures, reference is made to U.S. Pat. No. 4,332,254 (Lundquist), U.S. Pat. No. 4,323,071 (Simpson-Robert), U.S. Pat. No. 4,439,185 (Lundquist), U.S. Pat. No. 4,468,224 (Enzmann, et.al.), U.S. Pat. No. 4,516,972 (Samson), U.S. Pat. No. 4,538,622 (Samson, et.al.), U.S. Pat. No. 4,554,929 (Samson, et.al.), U.S. Pat. No. 4,569,347 (Frisbie), U.S. Pat. No. 4,571,240 (Samson, et.al.), U.S. Pat. No. 4,638,805 (Powell), and U.S. Pat. No. 4,743,230 (Nordquest), each of which are hereby incorporated herein in their entirety by reference thereto.
The use of the various devices in angioplasty procedures requires a fair degree of manual dexterity on the part of the physician performing the procedures and frequently one or more assistants are also required. The inflation and deflation of the balloon on the dilatation catheter for priming the catheter and venting air therefrom and for performing the dilatation can be particularly demanding.
Most commercially available inflation devices for angioplasty catheters are essentially syringes with pressure gauges attached thereto. They generally have two modes of operation. In one mode, the piston and attached piston rod of the syringe are free to move longitudinally within the inner bore of the syringe by pulling on a handle provided on the piston rod to pull a vacuum so as to draw inflation fluid into the bore of the syringe or by pushing on the handle to discharge such inflation fluid out the end of the syringe. In the other mode, the piston rod, which is threaded, is engaged with an element of the device so that the longitudinal movement within the bore is effected by rotation of the piston rod. For a more detailed description of such inflation devices reference is made to U.S. Pat. No. 4,743,230 which has been incorporated herein by reference. While these inflation devices have been effective for their intended uses, they have not always been very convenient for the physician to use particularly when changing from one mode of operation to another. Additionally, they could not always maintain a locked position under high pressure.
What has been needed and heretofore unavailable is an inflation device which is easy for the physician to use, particularly when changing the modes of operation. The present invention satisfies this need.